An alternating current supply is connected in series with a resistor R, as shown in the figure below.
The variation with time 
(measured in seconds) of the current 
(measured in amps) in the resistor is given by the expression
For the current in the resistor R, determine
the frequency,
the r.m.s. current.
To prevent over-heating, the mean power dissipated in resistor R must not exceed 
. Calculate the minimum resistance of R.
.
.
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